FCC Forms are cached by default by web agent to improve the web agent performance. This can be disabled by setting ACO EnableFormCache=No.

Refer to web server documentation to disable any web server specific cache settings . For e.g in case of IIS you could consider disabling Output caching (UserCache/Kernel Cache). For IIS it is also recommended to set ACO IISCacheDisable=yes

Clear browser cache by deleting browsing history or alternatively you can append a random querystring to ensure that it doesn't serve the web page from it's local cache (e.g you can try accessing login.fcc?1=1 , login.fcc?2=2 etc. )

To ensure that you are modifying the correct FCC page, the best way is to the enable web agent trace log and check the location where it is loading the forms from . For e.g.Here we can see that the web agent loaded the localized fcc form from forms_en-US directory rather than the default forms directory